Nonflammable fleon has conventionally been used as a refrigerant for a refrigerating cycle unit of refrigerators. However, fleon has recently been found to result in destruction of an ozonosphere (ozone layer). Accordingly, arrangements and agreements have been made regarding reduction in an amount of fleon to be used and limitation in use of fleon. Isobutane has been examined as the refrigerant for the refrigerating cycle unit of the refrigerator instead of fleon.
However, isobutene, which is a flammable material comprising hydrocarbon as a base, has the following problems. Some types of refrigerators are provided with a deodorizer for eliminating odor component in cold air. One type of such deodorizers utilizes decomposition of odor component by ozone produced by high-voltage discharge between a pair of electrodes. In the case where this type of deodorizer is disposed in the refrigerator using isobutane as the refrigerant, the high-voltage discharge between the electrodes would ignite such that isobutane would catch fire or burning of isobutane would thermally damage the deodorizer or its peripheral components.